Thread control mechanism



Dec. 5, 1933. 4 y C, w H'DOUBLER l 1,938,018

THREAD CONTROL MECHANIS'M Filed Sept. 17, 1930 2 Sheets-Sheet 1 w IUI (/f/f l l -Y L li m 1 |I\ Qll x 1 [lul H t f o L@ d m 1 m f l i m M 1m Q sl? w Dec. 5, 1933. c. w. HDOUBLER THREAD CONTROL MECHANISM Filed Sept. 17, 1950 2 Sheets-Sheet 2 I N VEN TOR.

Patented Dec. 5, 1933 UNITED STATES PATENT OFFICE Application September 17, 1930 Serial No. 482,553

18 Claims.

The present invention relates in general to new and useful improvements in thread control mechanism, particularly applicable to sewing machines and the like, and more specifically to family sewing machines of the lock stitch types.

Heretofore sewing machines have been equipped with various types of thread controls wherein the take-up lever and associated Ytension device are external adjuncts to the sewing machine and, being of light, fragile structure, are subject to breakage or damage. In such prior sewing machines correct threading of the needle, with relation to the tension and the take-up devices, is more or less a confusing problem to the casual sewer. Furthermore, the rapidly reciprocating take-up lever associated with such prior sewing machines is a menace to the operators fingers and flips the thread around indiscriminately and in a manner to permit twisting or catching which sometimes causes distorted stitches or a broken thread. Still another objectional feature in prior sewing machines, particularly those equipped with thread controlling mechanism comprising a (so-called) link take-up, is thel fact that, owing to necessity, the retarded action of the take-up lever occurring at one end of its rec'procal circuit must be utilized to drawy in the stitch, and this results in a looser stitch than might be expected from the same tension provided the uninterrupted sweep of the take-up lever to the opposite end of its circuit could be utilized to set the stitch.

It is the general object of the present invention to overcome the objectional features mentioned to provide thread control mechanism in which the thread and its take-up means are entirely enclosed and concealed from view within the frame of the sewing machine, to protect the thread and the operators fingers.

A further object of thek invention is to provide improvements in thread controlling mechansm whereby the thread is automatically engaged by the take-up memberduring each cycle of stitch forming operations without preliminary threading of said member.

Another object of the present'invention is to provide a thread controlling mechanism in which the take-up member will hold the thread in check against the pull of the descending needle until the point of said needle is about to enter the material, to prevent doubling of the thread ahead of the needle point, and then shed said thread to give it unrestricted action for looping the thread of the lower thread supply.

A further object of the present invention is to reverse the usual take-up action of prior sewing machines equipped with link take-up means and provide thread control mechanism in which the take-up lever draws up the slack thread and sets the stitch with one unretarded sweep to produce a tightly drawn in stitch.

Another object of this invention is to provide thread control mechanism having a take-up member which is readily adjustable to meet the requirements of any type of lock stitch sewing 05 machine.

A still further object of the present invention is to provide thread control mechanism which is of simple and eicient construction, easy running and practically noiseless.

These and other objects and advantages will be apparent from the following detailed description:

A clear` conception of embodiments of various features constituting the present invention may be had by referring to the accompanying drawings in which like reference characters designate the same or similar parts in the several views.

Fig. 1 is a side elevation of a new type of sewing machine embodying some of the features of the present invention, some parts having been broken away and other parts in section to show internal structure;

Figure 2 is a top view of the tubular arm of the machine with a portion of the cover broken away to disclose the take-up means within the arm;

Fig. 3 is a section through the arm, taken along the line 3-3 of Fig. 2;

Fig. 4 is a side view of a fragment of the head, with the face plate removed to show the tension device and the forward ends of the two grooves or channel, and intervening tongue;

Fig. 5 is a perspective view of the forked, V- shaped thread guiding and supporting member; and y Fig. 6 is a partial side elevation, particularly showing the thread guard and take-up lever.

Referring to the drawings,the numeral 4 indicates the tubular standard of a special type of sewing machine embodying the present invention. The standard 4 terminates in a horizontally extending hollow arm 5 having a head 5 formed integral therewith. The head 5 has a cylindrical, horizontally disposed well-like cavity or recess 6 in its upper end, within which is centrally disposed a pin 'Z adapted to loosely support a spool 8 containing the needle supply thread 9. In order to retain the spool 8 freely rotatable within the cavity 6, a cover 10 is pivoted to the head at the mouth of the well by a shouldered screw 11.

A fiat tension plate 12, having an upper edge curved to conform with the contour of the cavity 6, is suitably secured to the head just below said cavity. The tension plate 12 is provided with a turned out lip 12", for supporting the cover 10 when in closed position, and with a short stud 12a. A spring tension member 16, having an aperture 16', is mounted on the tension plate 12 by an adjustment screw 17, with the edge forming the aperture 16 surrounding the stud 12a.

The head has mounted therein, for reciprocation, the usual needle bar 18 which supports the needle 20, and is reciprocated by the usual mechanism mounted within the head and arm.

Two substantially horizontal grooves or channels 23 and 23', and an intervening tongue 40, are provided in the front wall of the arm 5, leading rearwardly from the tension plate 12 to the take-up zone which lies in back of the line of section 3 3.

The two grooves 23 and 23 provide a forming and guiding chamber, divided into two channels by the intervening tongue 40, wherein thethread 9 is formed into, and supported in, an elongated U-shaped loop which is made automatically engageable at its apex with a take up means (to be described later) by means of a forked, V-shaped member 27 secured to the rear end of the tongue 40 and to be later defined. And by this arrangement the portions of thread leading to and from the take-up zone travels in the separate channels to prevent snarling.

The tongue 40, forming one side wall of each channel 23 and 23', extends outwardly somewhat farther ,than the other two side walls of said channels to provide an entrance way for the thread when the face plate 24 has been secured. to the tongue 40 by a screw 25, see Fig. 3.

'Ihe face plate 24 is provided with a transverse slot 26 near the rear end thereof, and from said slot the rear end of the face plate is flared outwardly for threading purposes. The forked, V- shaped guiding and supporting member 27 (before mentioned), having a flat supporting shank, projects inwardly through the transverse slot 26 and is firmly supported by means yof said slot and the screw 25 which extends through the shank and face plate and is threaded into the tongue 40. A

Properly positioned the V-shaped portion of the member 27 will be directly to the rear of the tonguev40 andthe two channels 23 and 23' and will extend inwardly to where the crotch or apex of said member will be slightly inside of the rearward line of travel of the hooked end portion 35 of the take-up lever 35, as indicated by the dotted line a, and within the take-up zone.

During normal operation the thread is introduced to the take-up zone by drawing the thread 9 direct from the supply spool 8, under the tension member 16 and backwardly through the concealed groove or channel 23 behind the face plate 24. Reversing the direction of the thread around the ared out. rear end of the face plate 24 causes the loop of thread, thus formed, to slide down the forwardly inclined portion of the V- shaped member 27 and into the crotch thereof. The thread now advances forwardly and is drawn under a slightly flared point 24' of the face plate and thence over a headed stud 28. The stud 28 is provided with a tapered shank and is anchored in the tension plate 12, back of the face plate 24, with the upper side or periphery in line with the -thereon and thence draw the channel 23'. The stud 28 protrudes through an angular notch provided in the face plate between two slightly flared points 24'; and said notch is fashioned with a rounded apex which partially encircles the stud 28 and the radius of this circular portion is slightly greater than the radius of the tapered shank, to provide clearance for the thread to slide down the tapered shank portion of said stud to rest against the tension plate 12 behind the face plate 24 and in line with the rear side wall of the guiding channel 23'. When the thread 9 is drawn under the rearwardly disposed point 24 of the face plate, as before stated, and over and partially around the stud 28 it naturally slides down the` tapered shank of said stud and pulls the trailing thread into the lower channel 23" of the forming chamber, and behind the face plate. The thread now advances downwardly, back of the forwardly disposed point 24 of the face plate, to the needle through a recess 29 formed between the head and the face plate, this recess also being used to house illuminating means.

The top oi the standard 4, the gear housing 4l, and that portion of the arm 5 that lies in back of the line of section 33, is machined to an even plane lying substantially in the plane of a line through the center of the tongue 40. A thin plate 42 is secured to the top of the standard by screws 43. The plate 42 covers all moving parts below its plane, excepting the crank arm, as far forwardly as the line of section 3 3, to protect the thread but is cut away on the side facing the operator to approximately conform with. the curved contour of the guard 45 to establish an entrance to a threadway 47 between the gear housing 41 and the inner side wall of the arm 5 through which the lower portion of the thread loop travels during sewing operations.

There is also provided a specially formed thread guard 45 having a -raised portion 45' at the forward end which seats on top of the upper prong V-shaped member 27, where it engages the thread looped thereover. Furthermore the shape and disposition of the guard member 45 are such that the hook portion 35' of the take-up lever 35, with the engaged thread looped thereover, may carry said thread loop rearwardly outside of the curved edge of said guard to a predetermined point upper portion of the thread loop onto the top of the guard as indicated by the dotted line 9c when said lever will have completed its rearward thrust as indicated by dotted form 35.

This action is made possible by the facts: First, that in drawing up the slack thread, after looping the source of lower thread supply, the upper portion of the thread loop is under suiicient stress to assure a straight upper thread portion between the hook 35' and the top edge of the forked member 27, over which the thread slides, during the entire rearward thrust of the take-up lever, and, second, that the plane of the top edge of said forked member is suiiiciently above the plane of said hook that when the take-up lever will have completed the first three quarters of its rearward thrust, as indicated by the dotted form 35a, the

incline of the thread between the two said members will be sufllcient to allow the thread to be freely drawn onto the top side of said guard starting at the predetermined point indicated approximately by the reference character 45e. The guard 45 is also provided with a curved notch 45" adjacent the rear end thereof to (a) afford clearance for the upper portion of the thread loop adjacent the hook 35' during the final quarter of its rearward thrust, and (b) allow said hook to retain restraining engagement with said thread during a predetermined period of each cycle of sewing operation before said thread is forcibly shed by said guard as the hook portion of the take-up lever recedes under the guard during its return or forwardly directed thrust as will be hereinafter stated.

Rotary motion is transmitted to the needle actuating shaft 30 by means of a vertical shaft 3l and gears 32 and 33. Mounted on the extreme top of the vertical shaft 31 is a counterbalanced crank arm 34 which supports the curved takeeup lever 35 by means of a pivotal screw 36. A controlling arm 37, pivoted on the stud 38, is also pivotally connected with the lever 35 by a shouldered rivet 39.

When the crank arm 34 rotates, in the direction indicated by arrow, the reciprocating take-up lever 35, starting from the position shown in the drawings (see Fig. 2), travels rearwardly and pulls the thread 9 up by an unretarded sweep to complete a tightly drawn in stitch.

During the rearwardly directed, pull-up stroke of the reciprocating take-up lever 35 the hooked portion 35 thereof, after engaging the thread, travels substantially along the arc of a circle the entire length of its rearward course, as indicated by the dotted line a. The reversal of direction is here instantly made travel swerves slightly, and gradually away from the rearward line of travel and thereby establishes a very acute rear end to the reciprocal circuit travelled by the hook portion 35' of said take-up lever, and which will sometimes hereinafter be referred to as the acute end of said reciprocal circuit.

During the return, or forwardly directed thrust of the take-up lever, the hooked end portion 35 holds the thread in check against the downward pull of the descending needle until the needle point is entering the material. This prevents doubling of the thread ahead of the needle. At this point, however, the hooked portion 35' recedes under the thread guard 45 at a predetermined point, provided by the cut-away notch 45" in the thread guard 45 as before stated, and, thereby, sheds the thread to give it unrestricted action in looping the thread of the lower thread supply. Quickly following the shedding of. the thread by the take-up lever, the loop thrown out by the needle 20, during the beginning of its ascent, is engaged by the loop-taking element 50, below the bed plate, and, while drawing down sufficient thread from above to loop the thread of the source of lower thread supply, the cast off thread in the take-up zone is again drawn into the crotch of the forked, V-shaped member 27 and is thereon supported in the desired U-shaped loop and in readiness for another cycle of stitch forming operations.

After shedding the thread, as just described, the take-up lever, at its hooked end portion 35', continues an inwardly directed course (as indicated by the dotted line b) until about to again reverse its direction of travel when it swerves outand the reversed line of.

wardly in a at trajectory or elliptical course partially encircles the thread 9, now looped over and supported on the forked, V-shaped member 27, and automatically engages said hooked portion of said take-up lever passes rearwardly between the two prongs of said V-shaped member to complete another cycle of stitch forming operations, and, therefore, no attempt need be made to thread the take-up lever as is necessary in prior sewing machines.

The feature of a take-up means in which the reciprocating lever travels a circuit that is elliptical at one end and acute at the other is common to the various types of socalled, link take-ups embodied in various prior sewing machines of well known makes. However in all such prior machines, owing to the location of the take-up means within the vertical head, from which the reciprocating lever protrudes, and the fact that the thread is threaded through an eye at the extreme outer end of said protruding lever and, therefore, constantly under restraint of said lever during sewing operations, said prior sewing machines must needs utilize the retarded action of said take-up lever occurring at the elliptical end of the reciprocal circuit to draw in the stitch. Furthermore, the speed of the thread carrying end of such prior take-up means is so great during the first stages of the return thrust of the lever that auxiliary tension devices areprovided thread as said ing onto the material being sewed and, thereby,

doubling ahead of the descending needle point;

whereas in my invention, setting the stitch at the opposite or acute end of the reciprocal circuit, the speed of the hook portion of the take-up lever during the first stages of the return thrust practically coincides with the speed of the descending needle and therefore, aided by the notch 45 provided in the thread guard 45, is enabled to retain a restraining check on the downwardly drawn thread for a predetermined period of the sewing cycle, as heretofore stated, hence no auxiliary tension device is required.

It is here pertinent to state that in reversing directions at the elliptical end of the reciprocal the lever portion thereof travels a comparatively fiat trajectory course prior to th-e actual reversing point, and that, therefore, the pull-up speed of said lever on the thread lessens from a rapid pace to practically nil just prior to reaching said actual point of reversal. This pronounced retardment of speed allows the thread to slacken somewhat and results in a stitch that is not as tightly drawn in as is possible if the pull-upspeed is maintained to the end of the stitch forming operation as shown and described in my invention. This has been fully proven by impartial tests wherein the thread tension in each test was identical. Furthermore, this declaration is strengthened by claimsv made for various typesof link take-ups to the effect that the retarded, gradual setting of the stitch, as above described, is such as to prevent breakage of the thread-i. e. because the thread slackens enough to relieve the strain.

In my invention, however, the length of the thread between the tension and the eye of the needle, at the period of take-up stress, prevents any likelihood of thread breakage from the takeup action during normal sewing operations, and, furthermore, it is apparent that by utilizing the uninterrupted action of the reciprocating takeup lever at the acute end of the reciprocal circuit to draw in the stitch, as heretofore stated, I am circuit of a link take-up means the free end of s enabled to utilize a lesser tensionon the needle thread than would be possible under reversed con--v mechanism carried by .4. In combination,

ditions and produce the same results.

Having herein shown and described the thread control mechanism, novelly constructed to accomplish the various objects heretofore related, what I claim isu A1. In combination, a frame comprising abase and a hollow needle supporting arm disposedy above said base and having a spool support at its forward end, means within said arm for actuating a needle carried by the forward end thereof, and take-up means at the rear end of the arm for a looped engagement with the thread passing through said needle, said takeupy means being disposed entirely within said arm. l 2. In combination, a frame comprisinga base and a hollow needle supporting arm disposed above said base and having a spool support at its'forward end, driving means within saidA base, saidarm for actuating a needle supported `by the forward end portion of said arm, a motion transmitting member connecting said driving means and said mechanism, andYtake-up means at the rear end portion of the arm for hooked engagement with a threadv passing from the spool through the needle, said take-up means being operable directly from said transmitting member. y

`3. In combination, a frame' comprising a base and a hollow needle supporting arm disposed above said base, driving means within said' base, mechanism carried by said arm for actuating a needle supported by the forward end of said arm, a motion transmitting member connecting said driving means and said mechanism, and takeup means at the'rear for looped engagement with the thread .passing through said needle, said take-up means carrying a looped portion of the thread in a. substantially horizontal plane within said arm.

a frame comprising a base and a hollow needle supporting arm disposed above said base, driving means within said base, mechanism carried by said arm for actuating a needle supported by the forward end the said arm, a vertical shaft for transmitting motion from said driving means to said mechanism, and take-up means'at the rearward end portion of said arm for the thread passing through said needle, said take-up means being operable directly by the upper end of said shaft and being formed to l,carry a looped portion of the thread in a substantially horizontal 'plane entirely within said arm.

5. In combination, a frame having `an arm formed at its forward end with a recess for supporting a spool, means forming a concealed thread-way for guiding thread from said recess rearwardly toward the opposite end of `said arm,

take-up means disposed at the opposite end of said arm for receiving a looped portion of the thread, a needle carrier supported by the, forward portion of said arm, and means forming a concealed `thread-way for guiding the thread from its looped connection with said take-up'means forwardly to a needle associated with said carrier.

6. In combination, a frame. having an arm formed at its forward end with a horizontal cylindrical recess for supporting a spool, means forming a concealed thread-way for guiding thread from within said recess toward the opposite 'rear end of said arm, take-up means concealed withinthe opposite end of said arm for receiving a portionf looped end portion of said arml within the up means at the rear lOObed portion of the thled. a. needle carrier supported by -a forward portion of said arm, and

means forminga concealed reversely directed forme'd. at its forwardend with ing recess, means 'forming a concealed threadway for guiding thread in one direction from said recess toward the opposite rear end of said formed. at its forward end with a spool holder, a

Atake-up means at the rear end portion of the arm, means guiding the thread from the spool holder rearwardly to ithe take up means for engagement therewith, a needle reciprocally carried by the forward end of the arm. and other means for guiding the thread from its looped engagement with the take-up means forwardly to the needle.

9. In combination, a frame havingan arm formed at its forward end portion with a spool holder recess, a take-up means in the rear end portion of the arm, means within the arm for guiding thread rearwardly from the holder recess to the take-up means for looped engagement therewith, a needle reciprocally carried vby the forward end portion of the arm, and other means arm and spaced from the first mentioned guiding means for guiding the thread from its looped engagement with the take up means forwardly to the needle.

,10. In combination, a frame having an arm formed at its forward end portion with a spool holder recess, a take-up, means in the rear end portion of the arm, means within the arm for guiding thread rearwardly from the holder recess to the take-up means-for looped engagement therewith, a needle reciprocally carried bythe forward end portion of the arm, and other means within the arm and spaced from the first mentioned guiding means for guiding the thread from its looped engagement with the take-up means to the needle, said take-up means automatically releasing the thread shortly after the stitch is set to permit unrestricted -action in looping a thread of a lower source of thread supply.

11. In combination, a frame having an arm formed at its forward end portion with a thread spool holder recess and means for reciprocally carrying a needle, thread guiding means between the spool recess and the needle and a takeend portion of the arm for drawing rearwardly within the arm an elongated thread loop formed between the spool and the take-up means.

12. In combination, a frame having` an arm formed at its forward end portion with a recess for holding a spool of thread and means for reciprocally carrying a needle, a take-up means at the rear end portion of the arm for forming ary means adjacent the take-up means for supporting the loop in position for automatic engagement by the take-up means.

13. In combination, a frame having an arm formed at its forward end portion with a recess for holding a spool of thread and means for reciprocally carrying a needle, a horizontally movable take-up means within the rear end portion of the arm and entirely concealed from view for drawing rearwardly the slack portion of an elongated thread loop formed within the arm and between the spool of thread and the take-up means, thread guiding means between the spool recess and the needle, and means for supporting the thread loop in position for automatic engagement by the take-up means.

14. In combination, a frame having an arm formed at its forward end portion with a recess for holding a spool of thread and means for reciprocally carrying a needle for a predetermined cycle of sewing operation, a take-up means within the rear end portion of the arm for automatically engaging the thread looped between the spool and the take-up means during each cycle of stitch forming operation, thread guiding means between the spool holder recess and the. take-up means, and means for supporting the thread in position for automatic engagement by the take-up means.

15. In combination, a frame comprising a base and a hollow needle and thread supporting arm disposed above said base, concealed thread guiding means for forming said thread into an engageable loop and horizontally operable take-up means for engagement with said thread.

16. In combination, a frame comprising a base and a hollow needle and thread supporting arm disposed above said base, a vertical head block at the forward end of said arm, means for forming an engageable thread loop within the arm and a horizontally operable take-up means to the rear of said vertical head block for engagement with said thread loop.

17. In combination, a frame comprising a base, a-hollow needle and thread supporting arm disposed above said base, a vertically disposed head block at the forward end of said arm supporting reciprocal needle carrying means for a predetermined cycle of -sewing operation, means for forming and supporting a loop in the thread leading to the needle, horizontally operable takeup means for engagement with said thread loop and means for restraining the thread against the downward pull of the descending needle for a predetermined period of said cycle of sewing operation to prevent doubling of the thread ahead of the needle.

18. In combination, a frame comprising a base. a horizontally extending needle and thread sup* porting arm above `said base, a vertical head block at the forward end of said arm, thread guiding means concealed within the arm and a horizontally operable take-up means to the rear oi,I

said vertical head block for engagement4 with said thread; said take-up means comprising a lever having one end pivotally associated with a horizontally disposed crank arm and the other end thereof suitably formed for thread engagement, and a control arm having one end pivoted to the medial portion of said lever and the other end thereof pivoted to the horizontally extending arm.

CHARLES W. HDOUBLER. 

